Treatment equipment of organic waste and treatment method

ABSTRACT

In treatment equipment of organic waste provided with a high temperature and pressure treatment apparatus to produce a slurried material by conducting the high temperature and high pressure treatment of the organic waste, a dehydration treatment apparatus to recover the dehydrated solid matter by conducting the dehydration treatment of the slurried material and a water treatment apparatus to conduct the purification treatment of a separated liquid separated by the dehydration treatment apparatus, the treatment equipment of organic waste is characterized by having a crusher to crush said organic waste before conducting the high pressure and temperature treatment and providing to said high temperature and pressure treatment apparatus a steam blowing means to blow steam into the organic waste in said high temperature and pressure treatment apparatus, wherein said high temperature and pressure treatment apparatus is formed as a continuous reaction tank to which the organic waste is continuously supplied and to which the steam is blown from the said steam blowing means to cause the reaction while heating, pressurizing and agitating, and wherein said water treatment apparatus is provided with a membrane separation treatment apparatus to conduct the separation treatment via the separation membrane as a condensed liquid of the residual solid matter in the separated liquid.

This application is a National Stage of International Application No.PCT/JP2006/305223, filed Mar. 16, 2006, and which claims the benefit ofJapanese Patent Application No. 2005-129942, filed Apr. 27, 2005, thedisclosures of both applications being incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to treatment equipment of organic wastewhich utilizes the organic waste effectively into a fuel and the like bytreating the organic waste under high temperature and high pressure toslurry it and then dehydrating it to recover as a combustible solid rawmaterial, and also relates to a method for treating organic waste.

DESCRIPTION OF PRIOR ART

Heretofore, a method of the incineration or landfill treatment oforganic waste has been generally conducted as a method for treatingorganic waste such as organic sludge, animal and plant remainder or foodresidue generated from a water treatment apparatus to treat sewage, rawsewage and various industrial wastes. Especially, organic sludge istreated by a method of the incineration or landfill treatment aftercondensation and dehydration. However, in this method, the bulkiness ofthe organic waste is large because the moisture-content is as high as75-82% by weight even after condensation and dehydration of the organicwaste. In the case of entrusting the disposal to a professional companyor a firm, the cost to take over the wastes to be treated is expensive.Consequently, it is the present situation that a major portion of thecost to the drainage of waste water is largely dominated by this wastecollection fee.

In the landfill disposal, the residual operative years of the industrialwaste landfill disposal site is getting fewer and the cost to take overis getting higher and higher year by year. In the incinerationtreatment, the volume of the fuel consumption is large and the energycost is expensive because the moisture-content is high. Further, inrecent years the situation is that the incineration treatment itself isgetting more and more difficult due to the problem of dioxin included inthe exhaust gas and the incineration ash.

In view of the problem described above, there is provided a method toattempt the effective utilization of the organic sludge as a fuel andthe like by treating it under high temperature and pressure, andliquefying or gasifying it. As one of examples, there is a sludgeliquefaction apparatus which is provided with a dehydrator to dehydratethe organic sludge, a press fitting device for press-fitting thedehydrated sludge into the following preheater, reactor and cooler inseries, the preheater to preheat the dehydrated sludge to bepress-fitted by means of a heating medium heated by the cooler of thelater step, the reactor to heat the preheated dehydrated sludge with theheating medium and allowing it to react at a temperature of 250° C. ormore under a pressure of the vapor pressure or more at this temperature,the cooler to cool the reactant with the heating medium, an atmosphereopen type apparatus to open the cooled reactant to atmospheric pressure,a recovering apparatus to recover a combustible liquid in the reactantwhich is opened to atmosphere and a heating furnace to indirectly heatthe heating medium by burning the recovered combustible liquid (forexample, see Patent Document 1).

As another example, there is a method which comprises slurrying a lowercarbonaceous material such as various dusts and brown coal, conductingthe high temperature and pressure treatment to thereby separate oxygenin the carbonaceous material as carbon dioxide and to producecarbonaceous slurry and utilizing the produced gas and the carbonaceousslurry as a fuel (for example, see Patent Document 2).

Further, as another example, there is a method which comprisesconducting the strong dehydration treatment of sewage sludge, conductingthe high temperature and pressure treatment of the dehydrated sludge(about 150-340° C.) to produce the sewage sludge slurry and flashing offthe moisture by flash evaporation, followed by mixing with the adjuvantfuel to produce the quantity of heat controlled slurry fuel (forexample, see patent Document 3).

However, in the method or equipment to liquefy the sludge described inPatent Document 1, the liquefaction reaction to produce the oilysubstance from the sludge takes quite long time because the reactionrate is slow when the reaction is operated under a low temperature andpressure. Therefore, there are problems in that the equipment cost andequipment installation area are increased due to the increase of energycost and their excessive equipment. Accordingly, the operation isnormally performed under high temperature and pressure conditions inorder to obtain the efficient reaction rate. However, its temperatureand pressure are so high that the energy cost and the equipment cost ofthe reactor in high pressure design and of the preheater, the heater andthe like cause problems.

In the method described in Patent Document 2, since it is not thereaction to produce the oily material, the necessary energy is reduced.In this aspect it is an effective means as a method to attempt theutilization of the waste such as various dusts and sludge into a fuel.However, a large volume of viscosity adjusted water is needed fromoutside in order to slurry the waste. Especially, sewage sludge issupplied as dehydrated sludge and is highly viscous because the moisturecontent is 78-82% by weight. This causes problems in that the pressureloss in the feeding pipes and various types of equipment increases, thetransportation efficiency is decreased and the overall heat transfercoefficient is reduced. Thus, in order to obtain the sludge havingfluidity, the equipment becomes overextended since a further largevolume of viscosity-adjusted water is needed.

Further, in the method described in Patent Document 3, the pressure lossin the feeding pipes and various equipment becomes higher, thetransportation efficiency is lower and the overall transfer coefficientis lower at the time of heating as compared with the fluid feeding asdescribed above because the dehydrated sludge is further more highlydehydrated under the high temperature and pressure treatment to form thesolid matter. Therefore, there are problems in that the energyefficiency is inefficient and the energy cost is costly.

Also, among the types of organic waste to be treated, the organic wasteoften forms a lump partially or contains the admixture such as woodymaterial, fibrous material and hair. In this case, the higher heatingtemperature and pressure, and the longer treatment time are necessarywhen the organic waste is subjected to the high temperature and pressuretreatment in the later step as compared to the case in which the lumpand the admixture are not included.

-   [Patent Document 1] JP-B-7-80000-   [Patent Document 2] JP-A-9-505878-   [Patent Document 3] JP-A-6-246297

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The present invention has been made in consideration of the situationsdescribed above. That is, it is an object of the present invention toprovide treatment equipment and a method for treating the organic wasteby conducting the high temperature and high pressure treatment to slurryand then dehydrating it to recover as a combustible solid raw material,which is capable of reducing the energy cost and the equipment cost andof preventing the scaling in each component of the equipment and ofwhich the heating temperature, the treatment pressure and the treatmenttime of the organic sludge in the high temperature and pressuretreatment step are approximately equivalent to those of the case inwhich the organic sludge does not contain the lump of the sludge and theadmixture, even when the large lump of the sludge and the admixture arepresent in the organic waste.

Means to Solve the Problems

According to an exemplary embodiment of the present disclosure,treatment equipment of organic waste is provided with a high temperatureand pressure treatment apparatus to produce a slurried material byconducting the high temperature and pressure treatment of the organicwaste, a dehydration treatment apparatus to recover a dehydrated solidmatter by conducting the dehydration treatment of the slurried materialand a water treatment apparatus to conduct the purification treatment ofa separated liquid separated by the dehydration treatment apparatus,which is characterized by having a crusher to crush the above organicwaste before conducting the high temperature and pressure treatment andproviding to the high temperature and high pressure apparatus a steamblowing means to blow steam into the organic wastes in theaforementioned high temperature and pressure apparatus, wherein saidhigh temperature and pressure treatment apparatus is formed as acontinuous reaction tank to which the organic waste is continuouslysupplied and to which the steam is blown from the aforementioned steamblowing means while heating, pressurizing and agitating to cause thereaction, and wherein the water treatment apparatus is provided with amembrane separation treatment apparatus to conduct the separationtreatment via the separation membrane as a condensed liquid of theresidual solid matter in the separated liquid.

The aforementioned exemplary treatment equipment of organic waste has apreheating tank to preheat the organic waste during the period fromafter the crushing by the crusher to the supply to the reaction tank,wherein the preheating tank stores a spiral heat exchange agitation tubeto agitate the organic waste supplied into the aforementioned preheatingtank while preheating with means of heat of the aforementioned heatingmedium by swirling the heating medium while allowing it to flow into thetube.

The steam blowing means of the aforementioned exemplary treatmentequipment of organic waste has a tangent jetting direction nozzle torotate the organic waste with agitation by jetting the steam to thetangent direction from the jetting port formed at the outer peripheralwall in the organic waste.

The aforementioned exemplary treatment equipment of organic waste has aheat recovery apparatus to recover the quantity of heat of theaforementioned slurried material produced in the aforementioned reactiontank and to cool the slurried material by heat exchange with the heatingmedium.

The aforementioned exemplary treatment equipment of organic waste iscomprised of a first cooler to vacuum and flash the slurried material bythe aforementioned recovery apparatus and to heat-exchange the producedsteam with the heating medium and a second cooler to heat-exchange theslurried material cooled by the first cooler with the heating medium.

The aforementioned exemplary treatment equipment of organic waste has aslurry storage tank to temporarily store the slurried material and toadd water to the slurried material to mix it with agitation.

The aforementioned exemplary treatment equipment of organic waste has amethane fermentation apparatus to ferment an organic matter in theaforementioned separation liquid to thereby produce a methane-containinggas.

According to another exemplary embodiment of the present disclosure, amethod is provided for treating organic waste comprising a hightemperature and pressure treatment step of conducting the hightemperature and pressure treatment of the organic waste to produce aslurried material, a dehydration treatment step of conducting thedehydration treatment of the slurried material produced in theaforementioned high temperature and pressure treatment step to recover adehydrated solid matter and a water treatment step of conducting thepurification treatment of the separated liquid separated in theaforementioned dehydration treatment step, which is characterized byhaving a crushing step to crush the organic waste before the hightemperature and pressure treatment, wherein the high temperature andpressure treatment step is a continuous reaction step to blow steam intothe organic waste continuously supplied to the reaction tank whileagitating and to conduct the reaction at a temperature of 150-250° C.and a pressure of the steam pressure or more at said temperature for5-120 minutes and wherein the aforementioned water treatment stepincludes a membrane separation treatment step to membrane-separate theresidual solid matter in the separated liquid as a concentrated liquid.

In the aforementioned exemplary method for treating organic waste, theorganic waste is crushed to a size of 5 mm or less.

The aforementioned exemplary method for treating organic waste includesa preheating step to continuously preheat the organic waste in apreheating tank between the aforementioned crushing step and thecontinuous reaction step, wherein the preheating tank stores a spiralheat exchange agitation tube therein to agitate the organic wastesupplied into the aforementioned preheating tank while preheating withheat of the aforementioned heating medium by swirling the heating mediumwhile allowing it to flow into the tube.

In the aforementioned exemplary method for treating organic waste, thereaction tank is equipped with a tangent direction jetting nozzle to jetthe steam to the tangent direction from the jetting port formed on theouter peripheral wall and the organic waste in the reaction tank isrotated with agitation while heating by jetting the steam from thejetting port.

The aforementioned exemplary method for treating organic waste comprisesadding water to the slurried material to mix with agitation and elutinga water soluble inorganic salt content such as a phosphorus content anda chlorine content in the slurried material.

The aforementioned exemplary method for treating organic waste producesa methane-containing gas by conducting the methane fermentation of theorganic matter in the separated liquid.

Effects of the Invention

The simplification of the systemic constitution and the reduction of theequipment cost can be attempted by eliminating a heater for organicwaste which was conventionally needed during the high temperature andpressure treatment in the high temperature and pressure treatmentapparatus. The heating temperature, treatment pressure and treatmenttime of the organic sludge in the high temperature and pressuretreatment step can be approximately equivalent to those of the case inwhich the organic sludge does not contain the large lump of the sludgeand the admixture even when the large lump of the sludge and theadmixture are present in the organic waste because the organic waste iscrushed by the crusher before the high temperature and pressuretreatment. Further, the reaction efficiency by the uniform heating anduniform agitation of sludge in the reaction tank can be attained sincethe heating, pressurization and agitation are conducted by arranging theblowing means of steam. The obtained combustible solid raw material canbe effectively utilized as a variety of coal alternative fuels,especially the combustible solid raw material obtained by treatingsewage sludge as the organic waste can be quite effectively utilized asa cement raw material and calcination fuel because the obtained solidraw material includes a large amount of clay to be used for the rawmaterial of cement. Also, since the water treatment apparatus isprovided with a membrane separation treatment apparatus, the harddecomposable COD component produced by the high temperature and pressuretreatment can be removed and the soluble organic matter can berecovered.

The crushed organic waste is supplied to the preheating tank before itis supplied to the reaction tank, where it is preheated to apredetermined temperature. At this time, the spiral heat exchangeagitation tube through which the heating medium is flowing in thepreheating tank is swirled and the organic waste is agitated, hereby theheat efficiency of the heating medium in the preheating tank is enhancedand the scaling is prevented.

The organic waste can be agitated while heating by jetting the steam tothe tangent direction of the rotating nozzle from the jetting port ofthe outer peripheral wall in the organic waste within the reaction tank.

The energy cost can be lowered since the quantity of heat used in thereaction tank is recovered by heat exchange with the heating medium.

The heating mediums of which each temperature is different can beobtained from a first cooler and a second cooler. By circularly usingthe obtained heating mediums for the suitable use at each temperature,the effective utilization of the quantity of heat can be attempted.Also, the scaling is hard to occur because the temperature of theslurried material is gradually lowered.

By adding water to the slurried material to mix with agitation in theslurry storage tank, a water soluble inorganic salt content such as aphosphorus content and a chlorine content can be eluted from theslurried material.

When the organic matter is subjected to the methane fermentation by themethane fermentation apparatus, the methane-containing gas which iseffectively usable, for example, as a fuel of a boiler can be produced.

The simplification of the systemic constitution and the reduction of theequipment cost can be attempted by eliminating a heater for organicwaste which was conventionally needed in the high temperature andpressure treatment. The heating temperature, treatment pressure andtreatment time of the organic sludge in the high temperature andpressure treatment step can be approximately equivalent to those of thecase in which the organic sludge does not contain the lump of the sludgeand the admixture even when the large lump of the sludge and theadmixture are present in the organic waste because the organic waste iscrushed by the crusher before the high temperature and pressuretreatment. Further the reaction efficiency by the uniform heating anduniform agitation of the sludge in the reaction tank can be attemptedsince the high temperature and pressure step comprises agitating thesludge while blowing the steam into the organic waste continuouslysupplied to the reaction tank and causing the reaction at a temperatureof 150-250° C. and under a pressure of the steam pressure or more atthis temperature for 5-120 minutes. Especially, the combustible solidraw material obtained by treating sewage sludge as the organic waste canbe quite effectively utilized as a cement raw material and calcinationfuel because the obtained solid raw material includes a large amount ofclay to be used for the raw material of cement. Also, since the watertreatment step is provided with a membrane separation treatment step,the hard decomposable COD component produced by the high temperature andpressure treatment can be removed and the soluble organic matter can berecovered.

When the organic waste is crushed to a size of 5 mm or less, the heatingtemperature, treatment pressure and treatment time of the organic wastein the actual high temperature and pressure treatment step can beapproximately equivalent to those of the case in which the organic wastedoes not contain the lump of the sludge and the admixture even when thelarge lump of the sludge and the admixture are present in the organicwaste.

Further, the crushed organic waste is supplied to the preheating tankbefore it is supplied into the reaction tank, where it is preheated to apredetermined temperature. At this time, the spiral heat exchangeagitation tube through which the heating medium is flowing in thepreheating tank is swirled and the organic waste is agitated, hereby theheat efficiency of the heating medium in the preheating tank is enhancedand the scaling is prevented.

The organic wastes can be agitated while swirling the rotation nozzle bynon-driving force because the steam is jetted to the tangent directionof the rotation nozzle from the jetting port of the outer peripheralwall in the organic waste within the reaction tank.

When water is added to the slurried material to mix them with agitation,a water soluble inorganic salt content such as a phosphorus content anda chlorine content in the slurried material can be eluted from theslurried material.

When the organic matter in the separated liquid is subjected to themethane fermentation by the methane fermentation apparatus, themethane-containing gas which is effectively usable, for example, as afuel of a boiler can be produced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 Schematic flow diagram of the treatment equipment with referenceto Example 1 of the present invention

FIG. 2 Expanded plane view of the tangent direction jetting nozzleinstalled to the steam blowing means with reference to the Example 1 ofthe present invention

DESCRIPTION OF SIGN

-   2: crusher-   5: reaction tank (high temperature and pressure treatment equipment)-   6: steam blowing means-   6 a: tangent direction jetting nozzle-   9: slurry storage tank-   12: dehydrator (dehydration treatment apparatus)-   19: separated liquid tank (water treatment apparatus)-   20: methane fermentation apparatus-   22: membrane separation treatment equipment

BEST MODE FOR CARRYING OUT THE INVENTION

It is an object of the present invention to provide treatment equipmentand a treatment method of the organic waste which comprises conductingthe high temperature and pressure treatment to slurry it and thenrecovering it as a combustible solid raw material to attempt theeffective utilization as a fuel, wherein the viscosity-adjusting waterand energy to be used in the reaction are reduced as much as possible,thereby being capable of lowering the energy cost and the equipmentcost. The object of the invention has been accomplished by thecontinuous reaction method which comprises charging a constant amount ofthe organic waste into the continuous reaction tank equipped with asteam blowing means and then blowing the steam from the steam blowingmeans to cause the reaction for a predetermined time while heating,pressurizing and agitating. Since the organic matter in the separatedwater is subjected to the methane fermentation by the methanefermentation apparatus, the methane-containing gas that is effectivelyusable, for example, as a fuel of a boiler can be produced. Further, theremoval of hard decomposable COD component and the recovery of thesoluble organic matter produced in the high temperature and pressuretreatment can be conducted by installing the membrane separationtreatment equipment to a part of the treatment equipment.

The embodiments of the present invention are explained based on thedrawings. FIG. 1 is a schematic flow diagram for the organic sludge ofone of the embodiments of the present invention.

In FIG. 1, Sign 1 is a sludge storage tank of equipment for receivingthe organic waste, wherein the sludge storage tank 1 receives 70-80% byweight of the moisture content of the sludge. The sludge is organicsludge generated from the water treatment equipment to treat sewage, rawsewage and a variety of industrial waste. Sign 1 a is a sludge extractorto supply the stored organic sludge to the later step apparatus in apredetermined flow rate.

Sign 2 is a crusher to crush the organic waste. Sometimes, the sludge tobe treated (organic waste) forms a large lump partially and contains anadmixture such as a woody material, a fibrous material and hair. Thecrusher 2 crushes these to a size of 5 mm or less and homogenizes thesludge.

A particulate cutting machine, a crushing pump and a homogenizer may beemployed as the crusher 2. However, it is preferable that theparticulate cutting machine is used because it has excellent crushingability, homogenizing ability and treatment ability. The crusher 2 mayhave a constitution where a simple stage crusher is arranged or aconstitution of a two-stage crusher where a pulverizer is furtherarranged after the crushing of a course crusher.

Sign 3 is a preheating tank and heats the crushed sludge uniformly witha heating coil 3 a to 60-80° C. by circulating the circulating heatingmedium (90-120° C.) heated in a second cooler 8 described below througha spiral heating coil 3 a swirled by a swirling motor which is notshown. In this way, since the heating coil 3 a has a constitution thatcan be swirled, the heat efficiency of the circulation heat medium inthe preheating tank 3 is enhanced and the scaling can be prevented.

Sign 4 is a sludge supply pump, and the preheated sludge heated at thepreheating tank 3 is continuously supplied to the bottom of the reactiontank 5 under a pressure of 2.0-6.0 MPa·G.

The reaction tank 5 blows the steam into the pressurized sludge (organicsludge) supplied from the sludge supply pump 4, and the organic sludgeis liquefied by causing the reaction with agitation at a temperature of150-250° C. under a pressure of the steam saturation pressure or more(0.4-4.0 MPa·G) for 5-120 minutes.

Plural stages of the steam blowing means 6 are provided at the upperpart and lower part of the reaction tank 5 so that the blowing of thesteam is heated and agitated uniformly as much as possible. The steamblowing means 6 has a tangent direction jetting nozzle 6 a to rotate theorganic sludge with agitation while jetting the steam to the tangentdirection (see FIG. 2). The number of stage in which the steam blowingmeans 6 is arranged may be a single stage when the reaction tank 5 is asmall type, and is established in dependence upon the volume of thereaction tank.

The excess steam blown for uniform heating and agitation and the gasgenerated by the reaction are discharged in accordance with theadjustment of the pressure of the reaction tank 5, then blown into thebelow-mentioned first cooler 7 and used for agitation of the liquefiedsludge.

The below-mentioned coolers 7, 8 condense the steam blown into thereaction tank 5. The condensed water elutes a phosphorus content andchlorine content in the sludge. The phosphorus and chlorine contentgives an adverse effect to the quality of the coal alternative fuel as aproduct. Accordingly, the condensed water can improve the quality of theproduct.

Sign 7 shows a first cooler and it adjusts the pressure within thecooler to 0.1-1.0 Mpa·G, and cools the liquefied sludge to a temperatureof 120-180° C. by flash evaporation and recovers the quantity of heat ofthe sludge by means of the circulation medium by circulating thecirculating heating medium through the cooling coil 7 a.

Sign 8 is a second cooler and it adjusts the pressure within the coolerto from the atmospheric pressure to 0.1 Mpa·G, and cools the liquefiedsludge to a temperature of 80-120° C. by flash evaporation and recoversthe quantity of heat of the sludge by means of the circulation heatingmedium by circulating the circulating heating medium through the coolingcoil 8 a.

In the cooler 7 the outer surface of the cooling coil 7 a is washed bythe condensed water which is largely generated. On the other hand, inthe cooler 8 the amount of the condensed water is decreased and theself-washing effect is weak, therefore, it has a structure to rotate theheating coil 8 a just as the case of the preheating tank 3. Hereby, theheating efficiency of the circulating heating medium within the secondcooler 8 is enhanced and the scaling can be prevented.

Sign 9 shows a slurry storage tank, and the liquefied sludge, the gasgenerated at the reaction tank 5 and the like are sent to the slurrystorage tank 9. The generated gas is cooled by the condenser 10, andthen released to atmosphere through a deodorizing device 11. Thecondenser 10 is washed by the purified water that is separated at thebelow-mentioned membrane separation apparatus 22 in order to prevent theclogging at the condenser 10 caused by the solid matter accompanied bythe generated gas, and the washed water is allowed to flow into theslurry storage tank 9.

In the slurry storage tank 9 the separated liquid content from thedehydration is mixed with the liquefied sludge and purified water withagitation while rotating the agitation blade 9 a.

Sign 12 is a dehydrator, and the slurried sludge sent under pressurefrom the bottom of the slurry storage tank 9 by a slurry supply pump 13is separated into the solid matter and the liquid content. The moisturecontent of the solid matter is a degree of 45-60% by weight.

A decanter type centrifuge, screw press and belt press may be used asthe dehydrator 12, however, it is preferable that the decanter typecentrifuge is used.

Sign 14 shows a dehydration solid matter storage tank, where thedehydrated sludge (dehydrated solid matter) is temporarily stored.

Sign 15 shows a dryer, which heats the dehydrated solid matter sentunder pressure from the bottom of the dehydrated solid matter storagetank 14 by a dehydrated solid matter supply pump 16 to evaporate themoisture content and produces a solid fuel as an article. As the heatsource of the dryer 15, the circulating heating medium which was heatedby the first cooler 7 and which is further heated by the heat of aboiler 18 at the heating medium heater 17 is employed. The dehydratedsludge is heated to evaporate the moisture content by suppliedcirculating heating medium, thereby forming the solid fuel of thearticle. The evaporated moisture content is sent to the combustiondeodorant apparatus after the condensation by a scrubber or condenserand then released to atmosphere.

Sign 19 shows a separation liquid tank (water treatment apparatus),which stores the dehydrated separated liquid content temporarily whilerotating the agitation blade 19 a, and also provides the combined use ofan acid fermentation apparatus as the pretreatment of the belowmentioned methane fermentation apparatus 20.

Sign 20 shows the methane fermentation apparatus, which conduct themethane fermentation of the separated liquid sent under pressure fromthe bottom of the separation tank 19 by means of the separated liquidsupply pump 21. Since the organic matter with high concentration isincluded in the separated liquid from the dehydrator 12, amethane-containing gas is generated from the organic matter by themethane fermentation and the effective utilization as a fuel of theboiler 18 is attempted.

The methane fermentation tank which constitutes the body of the methanefermentation apparatus 20 includes upflow anaerobic treatment apparatus(UASB TREATMENT APPARATUS), floating type methane fermentation tank andthe like, however, CODcr is as high as 20,000-80,000. It is preferredthat the high-speed UASB treatment apparatus is used from the viewpointof an initial and running cost.

Sign 22 shows a membrane separation apparatus, which conducts theseparation treatment of the digested liquid after the methanefermentation treatment by separation membrane. The concentrated liquidis supplied into the dehydrated solid matter storage tank 14 in the caseof being possible of quality maintenance as a coal alternative fuel,however, it is treated as industrial waste when the quality isproblematic. The permeated liquid is drained as the purified water and apart of it is circulated into the slurry storage tank 9 as describedbefore.

The separation module used in the membrane separation apparatus 22includes a tubular module, a flat plate module, a hollow fiber moduleand the like. As a separation membrane, RO membrane (reverse osmosismembrane), UF membrane (ultra filtration membrane), MO membrane (finefiltration membrane) NF membrane (nano-filter membrane apparatus) andthe like are suitably selected, however, the nano-filter membrane or ROmembrane apparatus are preferably used in dependence with the draindischarging conditions. It is preferable that the structure of themembrane separation apparatus 22 in which a plurality of flat platemodules are laminated with a space in a predetermined distance and whichvibrates and rotates the modules is capable of preventing the fouling onthe surface of the membrane and of lowering the numbers of theseparation membranes.

In FIG. 1, sign 23 shows a first valve to adjust the flow rate of theslurried sludge supplied to the first cooler 7 from the reaction tank 5and sign 24 shows a second valve to adjust the flow rate of the firstcooling slurry supplied to the second cooler 8 from the first cooler 7.In FIG. 1, the chain line shows the circulation pass of the circulatingheating medium. The circulating heating medium heated by the heatingmedium heater 17 returns to the heating medium heater 17 via the dryingapparatus 15 and the first cooler 7. In another circulation pass of thecirculating heating medium, the circulating heating medium returns tothe second cooler 8 again via the preheating tank 3.

Example

Next, the method for treating the organic waste such as sewage sludge(herein after, simply referred to as sludge) using the treatmentequipment of the organic waste of the above constitution will beexplained with reference to the following examples.

The sludge with the moisture content of 70-85% by weight generated fromthe water treatment equipment is taken into the sludge storage tank 1 ata rate of 1,000 kg/hour. The received sludge is the dehydrated sludgewith the moisture content of 80% by weight, combustible content (C) of16% by weight and ash content (A) of 4% by weight obtained by thedehydrator, which is normally arranged to the water treatment equipment.However, it is not limited to the above.

The sludge extracted from the sludge storage tank 1 by the sludgeextracting machine 1 a is supplied to the crusher 2 via a pipeline L2.The sludge to be treated (organic sludge) is crushed to a size of 5 mmor less. Accordingly, even the sludge forms a large lump partially, andincludes an admixture such as a woody material, fibrous matter and hair,the sludge is homogenized by crushing the above-mentioned material. Insuch a manner, the crushing and homogenization of the organic sludge isable to lower the temperature, pressure and reaction time at thesubsequent reaction tank.

The crushed sludge discharged from the crusher 2 is supplied to thepreheating tank 5 via the pipeline L2. Here, the heating medium (90-120°C.) heated by the second cooler 8 is circulated through the heating coil3 a which is internally arranged and the crushed sludge is heated to60-80° C. by the heating coil 3 a.

The preheated sludge heated by the preheating tank 3 is discharged viathe pipeline L3 from the bottom of the reaction tank 5 and iscontinuously supplied to the bottom of the reaction tank 5 under apressure of 2.0-6.0 MPa·G via the piping L 4 by the sludge supply pump4.

In the reaction tank 5, steam is blown via the pipe line L5 into thepressurized sludge (organic sludge) supplied from the sludge supply pump4, and the reaction was conducted at a temperature of 150-250° C. undera pressure (0.4-4.0 MPa·G) of the steam saturation pressure or more atthis temperature for 5-120 minutes. Hereby, the organic sludge isliquefied and the liquefied sludge is agitated. By this agitation, theheating of the sludge is performed within ten minutes, so that thereaction temperature, the pressure and the reaction time can bedecreased by the rapid temperature elevation. Also, the precipitation ofthe heavy content is prevented by the agitation.

The blowing of the steam at the upper and lower part of the reactiontank 5 is performed from the jetting port formed on every 120° of theouter peripheral wall through the tangent direction jetting nozzle 6 ato jet the steam to the tangent direction.

The excess steam blown for uniform heating and agitation and the gasgenerated by the reaction is discharged upon adjusting the pressure ofthe reaction tank 5 and is blown into the below-mentioned first cooler 7to be used for agitation of the liquefied sludge.

The below-mentioned coolers 7, 8 condense the steam that has been blowninto the reaction tank 5. This condensed water elutes the phosphoruscontent and the chlorine content in the sludge. The phosphorus andchlorine content would give an adverse effect to the quality of the coalalternative fuel as a product. Thus, the condensed water enables theproduct to improve the quality. The sludge with the moisture content of89.71% by weight at the exit of the reaction tank 5 is sent underpressure of 1,252 kg/h. The sludge composition has the combustiblecontent (C) of 7.09% by weight and the ash content (A) of 3.19% byweight.

After that, the slurried sludge is supplied to the first cooler 7 fromthe proximity of the liquid surface of the reaction tank 5 via thepipeline L6 in which the first valve 23 is opened. Here, the pressurewithin the cooler is adjusted to 0.1-1.0 MPa, the liquefied sludge iscooled to a temperature of 120-180° C. by flash evaporation bycirculating the circulating heating medium through the cooling coil 7 ato recover the quantity of heat.

The first cooled slurry that passed through the first cooler 7 issupplied to the second cooler 8 via the pipeline L7 of which the firstvalve 24 is opened. Here, the pressure within the cooler is adjusted tofrom the atmospheric pressure to 0.1 MPa·G. Then, the first cooledslurry is cooled to a temperature of 80-120° C. by the flash evaporationand the circulating heating medium is circulated through the coolingcoil 8 a to recover the quantity of heat of the sludge by thecirculating heating medium. The sludge composition at the exit of thecooler 8 has the moisture content of 90.53% by weight, the combustiblecontent (C) of 6.53% by weight and the ash content (A) of 2.94% byweight.

The second cooled slurry that passed through the second cooler 8 and thegas generated at the reaction tank 5 is supplied to the slurry storagetank 9 via the pipeline L 8. The gas generated here is cooled by thecondenser 10 via the pipeline 9 and then is released to atmosphere viathe deodorant apparatus 11. The condenser 10 is washed by the purifiedwater which is separated at the below-mentioned membrane separationapparatus 22 in order to prevent the clogging at the condenser 10 causedby the solid matter accompanied by the generated gas. And the washedwater is allowed to flow into the slurry storage tank 9.

In the slurry storage tank 9, the separate liquid content from thedehydration is mixed with the liquefied sludge and the purified waterwith agitation while rotating the agitation blade 9 a. Accordingly, thewater-soluble organic salt content such as phosphorus content andchlorine content is eluted. This procedure is performed in order toenhance the quality of the solid fuel. The amount of the purified wateris adjusted in dependence with the concentration of phosphorus, chlorineand the like. The sludge composition at the exit of the slurry storagetank 9 includes the moisture content of 90.24% by weight, thecombustible content (C) of 6.73% by weight and the ash content (A) of3.03% by weight.

The slurried sludge discharged from the bottom of the slurry storagetank 9 via the pipeline L10, is sent under pressure to the dehydratorapparatus 12 by the slurry supply pump 13. Here, the slurried sludge isseparated into the solid matter and the liquid content. The moisturecontent of the solid matter is a degree of 45-60% by weight.

The dehydrated sludge dehydrated by the dehydrator apparatus 12(dehydrated solid matter) is temporally stored at the dehydrated solidmatter storage tank 14 via the pipeline L 11. After that, the hydratedsolid matter is passed through the pipeline 12 and sent under pressureto the dryer 15 via the pipeline L 13 from the lower part of thedehydration solid matter storage tank 14 by the dehydration solid mattersupply pump 16. The sludge composition at the exit of the dehydrator 12includes the moisture content of 60% by weight, the combustible content(C) of 27.58% by weight and the ash content (A) of 12.42% by weight.

In the dryer 15, the dehydrated solid matter is heated to evaporate themoisture and the article of the solid matter is prepared. As the heatsource of the dryer 15, the circulating heating medium which was heatedby the first cooler 7 and which is further heated by the heat of aboiler 18 at the heating medium heater 17 is employed. The dehydratedsludge is heated to evaporate the moisture content by suppliedcirculating heating medium, thereby forming the solid fuel of thearticle. The evaporated moisture content is sent to the combustiondeodorant apparatus after the condensation by a scrubber or condenserand then released to atmosphere. The sludge with the moisture content of10% by weight at the exit of the dryer 15 is sent under a pressure of133 kg/hour. The sludge composition here includes the combustiblecontent (C) of 63.08% by weight and the ash content (A) of 26.92% byweight.

The separated liquid separated from the dehydrator 12 is supplied to theseparated liquid tank 19 via the pipeline L 14. The separated liquidcontent from the dehydration is temporarily stored while rotating theagitation blade 19 a. The separated liquid tank 19 is used incombination with the acid fermentation apparatus as the pretreatment ofthe methane fermentation apparatus 20.

The separated liquid withdrawn from the bottom of the separated liquidtank 19 via the pipeline L 15 by the separated liquid supply pump 21 issupplied to the methane fermentation apparatus 20. Here, the separatedliquid is subjected to the methane fermentation. The organic matter withhigh concentration is included in the separated liquid from thedehydrator 12. Therefore, the methane-containing gas is produced fromthe organic matter by the methane fermentation and is effectivelyutilized as a fuel of the boiler 18 via the pipeline L 16. The amount offuel to be used is improved in 27.6% calculated by formula (1):(68.2−18.8)/68.2=0.724.

The digestion liquid after the methane fermentation treatment issupplied to the membrane separation apparatus 22 via the pipeline 17.The digestion liquid is subjected to the separation treatment by theseparation membrane and is supplied to the dehydration solid matterstorage tank 14 via the pipeline L 18 when the quality maintenance as acoal alternative fuel is possible. However, when there are problems onthe quality, the concentrated liquid is treated as industrial waste. Thepermeated liquid through the separation membrane is drained as thepurified water via the pipeline L 19, and the part of them is circulatedto the slurry storage tank 9 via the pipeline L 20 as described above.

Industrial Applicability

The present invention is useful for treatment equipment of organic wastethat is capable of recovering the organic waste such as raw sewage andindustrial waste treatment sludge as a cement raw material, acalcination fuel, a coal alternative fuel and the like.

1. A system for treating an organic waste comprising: a preheating tankto preheat the organic waste, wherein the preheating tank includes aspiral heat exchange agitation tube to agitate the organic wastesupplied into the preheating tank while preheating with heat of aheating medium by flowing the heating medium through the tube andswirling the tube; a pump to pressurize the organic waste; a hightemperature and pressure treatment apparatus following the preheatingtank and the pump, the organic waste being supplied to the hightemperature and pressure treatment apparatus under pressure from thepump, the high temperature and pressure treatment apparatus producing aslurried material by treating the pressurized organic waste from thepump at a high temperature and a high pressure; a steam blowing means toblow steam into the organic waste in the high temperature and pressuretreatment apparatus; wherein the high temperature and pressure treatmentapparatus is formed as a continuous reaction tank to which thepressurized organic waste is continuously supplied from the pump and towhich the steam is blown from the steam blowing means to cause areaction while heating, pressurizing and agitating; a dehydrationtreatment apparatus following the high temperature and pressuretreatment apparatus to dehydrate the slurried material from the hightemperature and pressure treatment apparatus, the dehydration treatmentapparatus producing a separated liquid product and a separated solidproduct, the separated solid product from the dehydration treatmentapparatus comprising a sufficient combustible content to produce a fuelproduct from the separated solid product; and a water treatmentapparatus following the dehydration treatment apparatus to treat theseparated liquid product from the dehydration treatment apparatus. 2.The system of claim 1, wherein the steam blowing means has a tangentdirection jetting nozzle formed in an outer peripheral wall of the steamblowing means, the jetting nozzle jetting steam from the jetting nozzlein the tangent direction relative to the outer peripheral wall of thesteam blowing means to rotate the organic waste in the high temperatureand pressure treatment apparatus with agitation.
 3. A system fortreating an organic waste comprising: a pump to pressurize the organicwaste; a high temperature and pressure treatment apparatus following thepump, the organic waste being supplied to the high temperature andpressure treatment apparatus under pressure from the pump, the hightemperature and pressure treatment apparatus producing a slurriedmaterial by treating the pressurized organic waste from the pump at ahigh temperature and a high pressure; a steam blowing means located inthe high temperature and pressure treatment apparatus, at least onejetting nozzle being formed in an outer peripheral wall of the steamblowing means to blow steam outwardly from the outer peripheral wall ofsteam blowing means and into the organic waste in the high temperatureand pressure treatment apparatus; wherein the high temperature andpressure treatment apparatus is formed as a continuous reaction tank towhich the pressurized organic waste is continuously supplied from thepump and to which the steam is blown from the steam blowing means tocause a reaction while heating, pressurizing and agitating; adepressurization apparatus following the high temperature and pressuretreatment apparatus, the depressurization apparatus producing adepressurized slurried material; a dehydration treatment apparatusfollowing the depressurization apparatus, the dehydration treatmentapparatus comprising a solid-liquid separator that is operable toperform an initial separation of liquid material from the depressurizedslurried material, the solid-liquid separator dividing the depressurizedslurried material into a separated liquid output and a separated solidoutput having an ash content and a sufficient combustible content toproduce a fuel product from the separated solid output; and a watertreatment apparatus following the dehydration treatment apparatus totreat the separated liquid output from the dehydration treatmentapparatus.
 4. The system of claim 3, wherein the depressurizationapparatus comprises a first cooler following the high temperature andpressure treatment apparatus to flash and cool the slurried materialfrom the high temperature and pressure treatment apparatus and a secondcooler following the first cooler to flash and further cool the slurriedmaterial cooled by the first cooler.
 5. The system of claim 4, furthercomprising a heat recovery apparatus to recover a quantity of heatreleased from the slurried material in at least one of the first andsecond coolers.
 6. The system of claim 3, further comprising a slurrystorage tank following the high temperature and pressure treatmentapparatus to store the slurried material, the slurry storage tankincluding a water inlet to add water to the slurried material and anagitator for mixing the slurried material and the water with agitation.7. The system of claim 3, wherein the water treatment apparatus includesa methane fermentation apparatus to digest organic material in theseparated liquid output to thereby produce a methane-containing gas. 8.The system of claim 3, further comprising a crusher preceding the hightemperature and pressure treatment apparatus to crush the organic wastebefore providing the organic waste to the high temperature and pressuretreatment apparatus.
 9. The system of claim 3, wherein the pumppressurizes the organic waste to a pressure of 2.0-6.0 MPa·G beforeproviding the pressurized organic waste to the high temperature andpressure treatment apparatus.
 10. The system of claim 3, wherein thehigh temperature in the high temperature and pressure treatmentapparatus is 150-250° C.
 11. The system of claim 3, wherein the highpressure in the high temperature and pressure treatment apparatus is ator above the steam saturation pressure at the high temperature.
 12. Thesystem of claim 3, wherein the high pressure in the high temperature andpressure treatment apparatus is 0.4-4.0 MPa·G.
 13. The system of claim3, further comprising a dryer following the dehydration treatmentapparatus to dry the separated solid output from the dehydrationtreatment apparatus, the dryer producing a solid fuel product from theseparated solid output.
 14. The system of claim 3, wherein the watertreatment apparatus includes a membrane separation treatment apparatusto recover a residual solid matter from the separated liquid output as acondensed liquid.
 15. The system of claim 3, wherein the separated solidoutput from the dehydration treatment apparatus comprises at least oneof a combustible content over 20% by weight and a moisture content of45-60% by weight.
 16. The system of claim 13, wherein the solid fueloutput from the dryer comprises at least one of a combustible contentover 60% by weight and a moisture content of 10% by weight.
 17. Thesystem of claim 3, wherein excess steam from the high temperature andpressure treatment apparatus is blown into a first cooler following thehigh temperature and pressure treatment apparatus.
 18. The system ofclaim 7, wherein the methane-containing gas from the methanefermentation apparatus is directed as fuel to a boiler, the boilerproducing steam for the steam blowing means of the high temperature andpressure treatment apparatus.
 19. A system for treating an organic wastecomprising: a pump to pressurize the organic waste; a high temperatureand pressure treatment apparatus following the pump, the organic wastebeing supplied to the high temperature and pressure treatment apparatusunder pressure from the pump, the high temperature and pressuretreatment apparatus producing a slurried material by treating thepressurized organic waste from the pump at a high temperature and a highpressure; a steam blowing means located in the high temperature andpressure treatment apparatus, at least one jetting nozzle being formedin an outer peripheral wall of the steam blowing means to blow steamoutwardly from the outer peripheral wall of the steam blowing means andinto the organic waste in the high temperature and pressure treatmentapparatus; wherein the high temperature and pressure treatment apparatusis formed as a continuous reaction tank to which the pressurized organicwaste is continuously supplied from the pump and to which the steam isblown from the steam blowing means to cause a reaction while heating,pressurizing and agitating; a dehydration treatment apparatus followingthe high temperature and pressure treatment apparatus to dehydrate theslurried material from the high temperature and pressure treatmentapparatus, the dehydration treatment apparatus producing a separatedliquid product and a separated solid product, the separated solidproduct from the dehydration treatment apparatus comprising a sufficientcombustible content to produce a fuel product from the separated solidproduct; and a water treatment apparatus following the dehydrationtreatment apparatus to treat the separated liquid product from thedehydration treatment apparatus.
 20. The system of claim 19, wherein theat least one jetting nozzle blows the steam in a tangent directionrelative to the outer peripheral wall of the steam blowing means torotate the organic waste in the high temperature and pressure treatmentapparatus.